how do you correct air flow theair condition ducts?

Answer 1

Assuming the ducts are of a diameter adequate to meet or exceed the flow capacity required and the blower speed is appropriate for the system in question, just add dampers to "throttle" the flow.
Dampers can only reduce the flow in the duct in which they are installed. If the flow is inadequate, you may need to increase the speed of the blower, or increase the diameter of the duct.
Balancing a system is important also. With no change in the volume of air supply, decreasing the flow of air in one duct will tend to increase the flow in other ducts. If that results in too much air in adjacent ducts, it may be necessary to reduce the blower speed.
Keep in mind that an air conditioning system or furnace requires the total volume of air flow (usually measured in cubic feet per minute) to be within a specified range.
If this is getting too complicated; that is why there are Heating, Ventilation and Air Conditioning (HVAC) Engineers. They design systems that are sized to prevent these types of problems.

Answer 2

Most of the ducts have a louver with a control leaver to adjust the flow where u can select where u want it to go.